Automatic stoker



Aug. 8, 1944. J. T. NORMAN AUTOMATIC STOKER 4 shets-sheet 1 Filed Aug. 12, 1940 (701s epfl. /Voma n 4 Sheets-Sheet 2 Filed Aug. 1 2, 1940 m K W a 3mm se/1471, /Vomn,

mi? a.

@tty/man A1185 8 1944 J. T. NORMAN n 2,355,101

AUTOMATIC STOKER Filed'Aug. 12, 1940 4 sheets-sheet 4 Jposeph /-Vomam Patented Aug. 8, 1944 UNITEDv STATES PATENToFI-ICE Joseph T. Norman, Huntington P., assignr,"

to Edith J. Norman, Hu,ntingtmiMills,v Pw N Application August 12, 1940, Serial'No." 352;33I)

1s claims. (o1.`11os5) My invention relates to coal burning furnaces and particularly to automatic stokers therefor.

Heretofore automatic stokers have been provided, but all those which have come to my attention are adapted for burning only the smaller sizes of coal such as buckwheat and rice. My invention, however, has for one of its principal objects to provide a stoker which will enable the furnace to burn coal of the larger sizes, either anthracite or bituminous coal, at will and with- .out change of apparatus.

Further, it is an object to provide a stoker which possesses the following advantages over other stokers now on themarket, namely:

It will burn either the larger sizes or the smaller sizes of coal and by burning the larger sizes will reduce the demand for smaller sizes of coal and increase the demand for the larger sizes; the larger sizes can be burned with natural draft; the feeder worms can be replaced withoutdisturbing the re; in case of power break-down or shutoffs, one can operate the Stoker by hand to hand re the furnace or boiler and thus ensure heat at all times; it will eliminate y ash; and it will be less expensive to manufacture and can be sold cheaper than other types now on the market.

Other objects will in part be obvious and in part be pointed out hereinafter,

To the attainment of the aforesaid objects and ends the invention still further resides in the novel details of construction, combination and arrangement of parts, all of which will be first fully described in the following detailed description, and then be particularly pointed out in the appended claims, reference being had to the accompanying drawings, in which- Fig, 1 is a vertical section on approximately the line I-I of Fig. 5.

Fig. 2 is a rear elevation of a boiler or furnace embodying the invention. f v

Fig. 3.is a verticalsection on the line 3-3v of Fig. 5.

Fig. 4 is a horizontal section on the line 4-4 of Fig.3. I f y 'f Fig. `5 is a vertical section on the central vertical longitudinal plane of the boilerv or furnace.

Fig. 6 is a detail vertical cross section of a modification of the invention.

In the drawings, in which like numbers of reference indicate like parts in all the gures, the base casting may be a solid one or, as shown, it may be hollow andcompolsedof the outer side and end walls I andthe inner side and endwalls 2 and 8 respectively. These wallsare spaced l'to form an air chamber, and are provided `with air,

. 9 if desired.

openings I2-in tl'ieinner walls 2 and I3 in the outer wall I, the latter opening being provided, preferably, with a regulating damper 39.

Side 'grates 3 are supported at their upper edges by bolts 4, loose enough to permit the 10W- er ends of the grates to move toward and from the rotary bottom grates'S.

Rods 5r are"c'onnected to Athe lower ends of the grates 3 "and-project through: the side walls 2 and I' of the base, and'have springs 6 and adjusting stop-nuts'lso constructed las to continuously tend to force "the :lower ends of the grates 3 toe Wardy the'grates 9 but be'capable of yielding under excessive forceto'permit the grates 3 to be swung away vfrom the lgrates 9, 'for a purpose which will later more fullyappear.

The innerlend walls ofthe lbase may also be formed as grates 8 above the level of the grates v'I'hegrates-,S comprise spirally grooved cylinders secured on shafts I Il which are journalled in suitable bearings 4I inthe base casting and project through the=frontf wallof the base to the outside VWhere their ends are squared as at 42 to receive; a crankfforpurposes .later explained.

Power vis applied by a suitable motor-driven shaft II y (hereinafter called the first motion shaft) which carries 'a gear 3| that meshes with a gear 32011 a stub shaft,V 33, the two shafts Il and 33 also carrying sprockets 35 around which pass chainsv 34 that also-pass around sprockets 25 on worm shafts 24 to drive the coal feed worms.

In `the embodiment vof `the invention shown in Figs. 1 and5 inclusive the coal is fed through side openings I5-in thetop section I4 of the boiler or furnace whichsits on the base -section and has the rebox 31 directly above the lire pot or combustion spaceI thatv lies between the grates 3 and 8 above the grates 9.

The' openings'I5 are located in the long side walls of the furnace-section I4 and receive the coalfrom the coalY ducts I 6 arranged at each side of the furnace and in which ducts I6 the coal feed worm `shafts 24'arelocated. The ducts IB arelonger than the' furnace section' I4 (see Fig.

5) "and mergewithf branches I1 of the conrnnon hopper 4-3-. From the openings I 5 to the back end oftheA branches:Ifl-:each duct I6 is tubular and in this -portionfof the duct the shaft 24'has a continuous worm-:I8 to-convey the coal from the hopper and along I6; 'Iheworms I8 terminate where the )feed openings f I5 begin,` Further along the shafts 24 are worm segments I9 and at the frontends-i'.r ec, where `the Yducts vI 6 terminate, or adjacent thereto-.theshafts havethrow-olf y paddles or vanes 20 which push the coal laterally The heated uid from within the jacket space" 'I of the Section 4 iS passed out to radiators '(not shown) through a suitable pipe or lpipes 23.;

The sprockets 25 have eccentrics lor crank pins; Y 26 to which links 2'I are connected, the'links also" being connected to rockingleversl28 which carry gravity actuated (preferably) pawls 29 that engage with ratchets 30 on the shafts 9.

In the modified form `shown in Fig. 6V the entire stoker and grate mechanism'is constructed asfaunit with the base. This Vform is for use'withold furnaces where the ordinary grate carrying base is removed and the new-base unit replaces'it.

Coal of any size desired is placed in the hopper 43 and gravitates to the branchesH. From the branches II-the coal-is fedwith the "short worms I8 intoj the ducts It` which; together with worm segments I9, convey thecoalthe entire length of the fire box, thus' effecting an even distribution of the coal on theflre.' By this method of feeding the -coal into .the fire' box theV` ashes are forced downward to the grates 9. Thisr eliminates bridging and hollow spots in the fire bed.l The I 5 feeders I5 are, preferablyV placed on a downward incline so that all bridging and hollow spots in the re are eliminated; 'Ihe ashes are forced to the grates and removed from the vfire'boxv in a practical manner without the use of bars or pokers to breakbridging. J t

The spiral grates 9 are cylinders having` spiral grooves about one-half inchdeep and' three-quar-A ters inch wide. This allows the ashes to fall in the Vgrooves and be discharged into the ash-pit, or container, without gouging the frefor upsetting the re bed. As the surfaces ofthe grates 9 revolve smoothly step by stepunder the ash bed, thus keeping the fine dustfrom choking the fire; this allows the fire to burn freely and evenly; When coal is burned under natural draft the ashes are finer and softer than whena blower is used. Should a clinker form, it is forced down on the spiral grates andl intothe grooves and is broken and discharged into the ash-pit. Should4 a piece of iron or other foreign matter happen to get into the fire and be too large to pass'through the grates and the spirall grooves, the side gratesy 3 are so arranged in sections and held yieldingly bythe coil springs that-.they canbe forced open to allow the iron or foreign matter to pass this eliminates the breaking of any. part of thelma-` chine. 'M

I have found thatvwith my apparatus very sat# isfactory results are obtained; breakage is elimi-t nated, no finecoal ordust is permittedto collect around the worm feed, Abut is distributed on the fire and isburned quickly, thuseliminati-ng wearvv on the worm feed. If either feeder should need repairing or replacing,Y it can be done without disturbingv the fire or shutting off the heat of the furnace and the furnace can be firedby vhand by using a crank on the rshaft ends' 42until repairs are complete; The furnacel has a door` 36A to the combustion chamber.

In the form shown in Fig. 6 the base has a filler 3S to give a horizontal seat for the top section |43.

In Fig. 6 those parts having like functions and similar constructions to those corresponding parts of Figs. 1 to 5 have been given the same reference number plus the index letter a, so a detailed description of the same is thought to be unnecessary. The walls of the extension filler 38 may be lined with fire brick (not shown), if desired.

Operation In general, the shaft I I is driven at a predetermined speed to impart proper rotation to the shaftsZlI to feed the required amount of coal con- `stantly to the fire box, while shaft I I is running. v The rotation of shafts 24 also imparts a step by step movement to shafts ID via the cranks 26 Iconnecting links 21, rocking levers 28, and pawl and ratchet devices 29, 39. This step by step movement is timed in cooperation with the feed of coal so as to remove suflicient ashes so as to keep the re bed always at a constant level and hence obtain a uniform firing.

It will be obvious to anyone having practical skill and experience in the art that when starting a're in the furnace, if the fuel level is first brought up to the top of the passages I5, and the worms I8 and the rotary grates 9 are timed to cooperate with each other,` the fuel being forced from opposite sides of the furnace through the passages I5 will cause a downward pressure to be applied to the coal in the furnace chamber; this downward pressure will in turn force the Y ashes toward the grate, where anyclinkers will be sheared and broken up, thus keeping the fire bed always at a constant level and obtaining thereby a uniform ring and an efficient operation.

H In the normal operation of applicants Stoker the ducts or passages I5 and I5 are kept full of f uel and the fuel level inthe chamber of the furnace is approximately that of the line 4--4 of Figf`3. Y

' The-'outside ends of the various shafts II, 24 and I0 are provided with crank-receiving portions so that they may be turned by hand should power failure occur or should it be found desirable to hand-operate the same for any purpose.

Theentire furnace is preferably enclosed in a heat insulating jacket or box 40.

From the-foregoing description, taken in connection with the accompanying drawings, it is thought that the construction and advantages of the invention will Ibe clear to those skilled in the art to which it-relates.

WhatI claim is:

1. In apparatus of the class described, a body enclosing a fire chamber having end andside walls, approximately upright grates extending along said side walls, spirally grooved rotary grates extending between said end walls and locatedbetween the lower portions of said upright grates, coal ducts located at the outer sides of said' body above said grates with their axes eX- tending in the same general'direction as the rotaryy g'rates, said coal ducts having side coalfeed openings extending the length of the fire chamber" for delivering coal into the re chamber, coalfconveyor shafts having coal feedingI and pushing means located in said ducts for conveying-ltlie coal along said ducts and forcing it into the'sidey coal-feed openings and into the fire and forcirigthe ashes down into the grates, and

means to impar-ti rotation tol saidooalv conveyor V2. In apparatus of the class described, a body enclosing a re chamber having end and side walls, approximately uprightV grates extending along said side walls, spirally grooved rotary 'grates extending between said end walls and'located between the lower portions of said upright grates, coal ducts located at the outer sides of said body above said grates with their axes extending in the same general direction as'thelrotary grates, said coal ductsv having side coal-feed openings extending the length of the fire chamber for delivering coal into the fire chamber, Icoal conveyor shafts having coal Vfeeding land pushing means located in said ducts for conveying the coal along said ducts and forcing it into the side coal feed openings and into the fire and forcing the ashes down into the grates, and means to impart continuous rotation to said coal conveyor shafts and intermittent rotation to said rotary grates in timed relation to each other for purposes described.

3. In apparatus of the class described, a base section and a top section set on the base section, said top section having a combustion chamber and said base section having akre chamber which is vprovided with side and end walls, upwardly extending side grates in said re chamber, rotary grates formingV the bottom of vsaid fire chamber and arranged to Vrotate on axes extending from adjacent one end wall to' adjacent the other end wall of said fire chamber, and coal-feeding means located above and at the sides of the fire for forcing coal in downwardly-inwardly inclined directions into the fire chamber to force the fuel in said chamber downwardly, in virtue of all of which the ashes are forced to the grates and removed by the same.

4. In apparatus of the class described, a base section and a top section setv on the base section, said top section having a combustion chamber and said base section having a fire chamber which is provided with side and end walls, the end walls of said re chamber being slotted to constitute end grates, upwardly extending side grates in said fire chamber, rotary grates forming the bottom of said fire chamber andarranged to rotate on axes extending from adjacent Aone end wall to adjacent the other end wall of said K4fire chamber, and coal-feeding means located above and at the sides of the rechamber'for feeding coal into the fire chamber in downwardlyinwardly inclined directions from opposite sides of the fire chamber and conse'quentlyapplying downward pressure to the fuel in said chambers, in virtue of all of which the ashes are forced downward to the grates and removed by the same,

5. In apparatus of the class described, a base section and a top section set on the base section, said top section having a combustion chamber and said base section having la fire chamber which is provided with side and end walls, `up wardly extending side grates in said fire chamber, rotary grates forming, the bottom of 'said fire chamber and arranged to rotate on axes extending from adjacent one end wall to adjacent the other end wall of said fire chamber, coal-feeding means located above and at the sides of the vfire chamber for forcing coal into the fire chamber from opposite sides thereof in downwardly-1in# wardly inclined directions and consequently applying a downwardpressure to the coal within said chambers, in virtue of all of which the ashes are forced downward to the grates in downwardly-inwardlv-inclined. directions, and means to effect continuous operation of said coal-deliver"- ing means while effecting intermittent rotation of said rotary grates.

6. In apparatus of the class described, a base section and a top section set on the base section, said top section yhaving a combustion chamber vand said base 'section having a re chamber which is provided with side and end walls, upwardly'extending side grates in said re chamber, rotary grates forming the bottom of said re chamber and arranged tov rotate `on` axes extending from adjacentone-e'nd wall to adjacent the other end wall of said fire chamber, and coal-feeding means located above and at the sides of the re chamber for forcing coal' into the fire chamber` from opposite sides thereof in downwardly-inwardly inclined directions and consequently applying a downward pressure to the coal within said chambers, in virtue of all of which the ashes are forced downward to the grates, said side gratesbeing laterally yieldably-supported in place with their lower portions spaced from said rotary grates a predetermined distance and adapted to yield should foreign matter tend to jam between the side grates and the rotary grates'.

7. In a structure'of the character described, a base section and an upper section, the latter enclosing acombustion chamber and the former enclosing a re chamber, side grates loosely mounted at their tops to said base and yieldably connected at their lower portions to said base so as toV be capable of vlateral movement, rotary grates located adjacent the lower extremities of said side grates and spaced apart with their axes parallelling said side grates, side-feeding coal conveyors Vfor simultaneously feeding coal over the full length of there" in the lire chamber from both sides in inwardly-downwardly-inclined directions, land means -to operate' said coal' con# veyors and said rotary grates in harmony.

8. In astructure of the character described',"a base section and an upper-section, the latter enclosing 'a combustion chamber and' the Vformer enclosing a re chamber; side grates loosely mounted at their tops to said base and y'ieldably connected 'at their lower portions to saidbase so'as to' be capable' of lateral movement, rotary grates located adjacent the "lower extremities of said side grates and spaced apart with their axes parallelling'said side grates, side-feeding coal-conveyors for" simultaneously depositing coal over the full `length of the re in the rechamber from both'sides, and means to operate said coal conveyors and said rotaryfgrates inharmony, said coal-feeding means comprising two longitudinal coal ducts one on each outer side of the base section and two coal conveyors and shafts cooperating withthe respective longitudinal coal ducts, individual hopperele'mentsone for 'supply-v ing each coal duct, andinwardlydownwardly-in clined coal ducts through which the coal is forced from the longitudinal coal ducts'to the combustionchamber.

9. In a structure of the class described,'a base section land 'a top section, said base section enclosing ia' fuel and vash cntainingspace, said top section-enclosing a combustion chamber which communicates with said fuel' and ash contain#- ing space, coal ducts on the outer sides of said top section, said top section 'having longitudinally disposed laterally discharging coal-feeding 'openings communicating withsaid combustion cha'm ben-'rotary bottomig'ra'tes an'dflat side grates in said fuel and ash containing space below said coal feed `-openings, `coalfieeding means. in:v said .coal ducts, and means to operate. said coal-feed.- ing means and said rotary gratesV in harmony, said rotary grates comprising spirally grooved rollers. g

10. In a structure of; the class described; a. 'base section -and'a top section,v said base sectiongenclosing a fuel and ash containing space, saidtop section enclosing a' combustion chamber which communicates with said fuel. and, ash `containingspace, coal ducts Von the outer sides of said top Section, said top section having longitudinally disposed-laterally discharging coal-.feeding openings communicating with said combustion charnber, spirally grooved rotary bottom grates and fiat side grates in said fuel and ash containing space below said coal feed openings, coal-feeding means in said coal'ducts, means to operate said -coalfeedingvmeans 'and said rotary grates infharmony, said means tofoperate comprising'a rst motion shaft, power transmitting connections be- Y tween'said rst motion shaft and said coal-feed ing means for imparting continuous motion to said coal-feeding means, and ratchet and pawl devices operatively connected with said coalfeeding means and with said rotary grates for imparting intermittent rotation to said rotary grates during the ycontinuous operation of said coalfeeding means.

11. In a structure of the class described, a base section and a top section, said base section enclosing a fuel andash containing space, said top section enclosing a combustion chamber which communicates with said fuel and ash containing space, coal ducts on the outer sides of said top section, said top section having longitudinally disposed laterally discharging inwardly-downwardly-inclined coal-feeding openings communi; eating with said combustion chamber, rotary bottom grates and flat side grates in said fuel and ash containing space, coal-feeding means in said coal ducts, and means to operate said coal-feeding means and said rotary grates in harmony. 12.' Inapparatus of the class described'a base casting enclosing achamber divided horizontally by longitudinally disposed rotary'grates into an upper fuel and ash containing chamber and a flower ash receiver, swingably mounted plate grates located in the fuel and ash containing chamber at the sides of said rotary grates and cooperating with the same to hold the fuel and ash, means yieldably supporting said plate grates with their lower portions spacedlaterally from said rotary grates, said rotary grates being sim-- ilarly-spaced apart, said base casting including `elongated longitudinally extending downwardly inclined coal-feeding openings above the grates, coal ducts located outside the base and having elongated openings registering with said coalfeeding openings, rotating vshafts having coal feeding worms and throw-olf paddles located in said ducts for conveying the coal along the ducts and delivering it uniformly to said coal-feeding openings and forcing the coal through said openings into the rst mentioned chamber, said base casting having' a nat topto receive the heatl exchange section of a furnace or boiler, and means to operate said coal-feeding shafts and said rotary grates in harmony. f a

13. In apparatus of the class described, la base casting enclosing a chamber divided horizontally by longitudinally disposed rotary grates into an upper fuel and ash containing-chamber and a lower ash receiver, swingably mounted plate gratesy located in kthe fueland ash containing chamber at` the sides of said rotary grates and cooperating with the same to hold the fuel Aand ash, means yieldably supporting said plate grates with their lower portions spaced laterally from said rotary grates, said rotary grates being similarly spaced apart, said base casting including elongated longitudinally extending coal-feeding openings above the grates, coal ducts located outside the base and having elongated openings registering with said coal-feeding openings, and rotating shafts having coal feeding worms and throw-olf paddles located in said ducts for conveying the coal along the ducts and delivering it uniformly to said coal-feeding openings and forcing the coal through said openings into the rst mentioned chamber, said base casting having a flat top to receive the heat exchange section of a furnace or boiler, said rotary coal-feedingshafts and said rotarygrates having extended shaft portions to receive a hand crank.

14. In apparatus of the class described, a base casting enclosing a chamber having an upper re box, a lower ash receiver and an intermediate chamber, said intermediate chamber being bounded at the ends by perforated walls, and at the sides by imperforate walls, a rotary grate constituting the bottom of said inermediate chamber, vside grates adjacent but spaced from said imperforate walls, said side grates being yieldably supported in placer with their lower portions spaced from said rotary grates a predetermined distance and adapted to yield should foreign matter tend to jam between the side grates and the rotary grates, means for turning said rotary grates, and means for passingvair to said grates.

15. In apparatus of the class described, a base casting enclosing a chamber havingl an upper fire box, a lower. ash receiver and an intermedie ate chamber, said. intermediate chamber being bounded at the ends by perforated Walls, and at the sides by imperforate Walls, a rotary grate constituting the bottom of said intermediate chamber, side grates adjacent `but spaced from said imperforate walls, said side gratesv being yieldably supported in place with their lower portions-.spaced from said rotary grates a predetermined distance and adaptedA to yield should foreign mattter tend to jam between the side grates and the rotary grates, means for turning said rotary grates, means for passing air to said grates, andmeans for forcing fuel into said upper fire box from opposite sides in an inwardly-downwardly-inclined direction, by virtue of all of which bridging of the re and formation of hollow spots in the re is avoided.

16. In apparatus of the class described, a structure enclosing a chamber, a clinker shearing grate located in the bottom of said chamber, coal conveyors located along each side of said chamber a predetermined distance above the grate, passages extending approximately the full length of said chamber and'inclined downwardly-inwardly from said coal conveyors to said chamber, means for operating said conveyors to push the coal through said inclined passages into said chamber and force the solid contents of said chamber downwardly, and means for operating said conveyors and said grate in timed relation, in virtue of allofwhich the ashes are forced to the grate, bridging is prevented, and clinkers are broken up.v Y 'y JOSEPH T. NORMAN. 

